The present disclosure relates to user interfaces and visualization of audio data.
Audio signals including audio data can be provided by a multitude of audio sources. Examples include audio signals from an FM radio receiver, a compact disc drive playing an audio CD, a microphone, or audio circuitry of a personal computer (e.g., during playback of an audio file).
When audio signals are provided using microphones, one or more of the microphones are usually associated with particular audio signals, e.g., a musician playing an instrument in an orchestra or a person singing in a band. Additionally, the number of microphones used to capture particular audio signals can be high. In such a setting, it is not uncommon to collect audio signals using microphones from thirty or more sources. For example, a drum set alone may require five or more microphones. Individual groups of instruments can have one or more microphones in common (e.g., in an orchestral setting). Additionally, single instruments are often exclusively associated with one or more microphones.
Audio sources, regardless of the way the audio signals are provided (i.e., whether providing signals using microphones or not), provide signals having different properties. Examples of properties include signal intensity, signal kind (e.g., stereo, mono), stereo width, and phase (or phase correlation, e.g., of a stereo signal).
The process of modifying the properties of multiple audio signals in relation to each other, in relation to other audio signals, or combining audio signals is referred to as mixing. A device for such a purpose is referred to as a mixer or an audio mixer. A particular state of the mixer denoting the relationship of multiple audio signals is typically referred to as a mix.
Generally, an audio mixer has a number of input channels, busses, and output channels. The audio mixer can selectively route the audio signals from particular input channels to one or more output channels. In the mixer, audio signals can be conditioned according to parameters specified by a user. Conditioning can include, for example, adjusting the signal intensity (i.e., the mixer channel output level) of an overall audio signal or adjusting the signal intensity in a specified frequency range. Parameters can include, for example, values for applying a gain to an audio signal (e.g., by increasing or decreasing the overall intensity of the signal) or values for adjusting the signal intensity over a specified frequency range (e.g., as part of an equalization operation).
An audio mixer generally has a number of faders, also referred to as sliders or attenuators. Each fader controls the intensity of an audio signal on an input channel or a group of input channels. This structure exists in software as well as in hardware mixers. Generally, to adjust both the individual intensities of the audio signals and the overall signal intensity of a mix, several adjustments of each fader can be performed in order to achieve a desired result. For example, different faders can be adjusted to set the intensity of each signal at a desired level in relation to the other audio signals and setting the combined audio signal of all the audio sources, i.e., the overall signal intensity.
In a digital audio workstation (DAW), the layout of an audio mixer is usually derived from an analog counterpart and, therefore, usually involves a number of channel strips. For example, an audio source is connected to the “top” of a channel strip and the signal runs through a series of components, e.g., a gain stage, an equalizer, a compressor, one or more aux sends, one or more bus sends, a pan/balance control, and a fader, before being routed to an output or to a combiner, e.g., a stereo summing bus.
Usually, interaction with a user interface of a software mixer involves a cursor controlled through a pointing device, e.g., a mouse, trackball, touchpad, or joystick. Adjustments to a slider control type mixer are made, for example, by positioning the cursor over the knob of a graphic representation of a fader, holding down a button of the pointing device, moving it to the desired position, and releasing the button. Another kind of input device may be employed, e.g., a keyboard, keypad, or dedicated hardware controller. In any case, several adjustments of the faders are used to set the intensity of a number of audio signals relative to each other and for setting the overall signal intensity.
The process of mixing can include a display or visualization of audio properties. Signal intensity, for example, is traditionally conveyed using level meters, such as defined in the standards IEC 60268-10, IEC 60268-17, and IEC 60268-18. An example for a level meter is a VU meter or volume unit meter. A VU meter can be implemented as a magnetoelectric VU meter in which a needle is moved from an initial position towards another position according to the flow of electric current through the meter. Other properties of the signal can also be visualized, e.g., using phase correlation meters, peak level meters, or goniometers.
Properties of audio signals have been visualized, e.g., using analog meters, before the wide use of digital electronic equipment. As a result, for most of the traditional devices for visualization of signal properties a digital equivalent for use in software user interfaces has been devised. Thus, for example, the controls of a digital audio mixer can include a visual representation of analog controls (e.g., an analog VU meter) in order to provide a familiar representation of the device traditionally used.